Composite Memory Device, Data Wiring Method And Program

ABSTRACT

There is provided a composite memory device including a recording medium and nonvolatile recording medium and in which data is written to and read from the recording mediums on the basis of a common file system, the recording medium ( 10 ) having a first data area, the nonvolatile recording medium ( 11 ) having a second data area and an identification information table to manage the first and second data area collectively. The device further includes an information selector ( 14 ) to select positional information including predetermined identification information on the basis of the identification information table, converter ( 15 ) to convert positional information selected by the information selector ( 14 ) into position information corresponding to the first data area or into positional information corresponding to the second data area, first writing unit to write data supplied from a host device to the first data area and a second writing unit to write data supplied to the host device to the second data area.

TECHNICAL FIELD

The present invention relates to a composite memory device including arecording medium and nonvolatile memory medium to write and read data onthe basis of a common file system, and a data writing method andprogram, for writing data to the composite memory device.

This application claims the priority of the Japanese Patent ApplicationNo. 2004-117120 filed in the Japanese Patent Office on Apr. 12, 2004,the entirety of which is incorporated by reference herein.

BACKGROUND ART

A hard disk drive (HDD) has been used in the past as an external memorydevice for use with personal computers (PC) and the like. With theimplemented technique for a higher recording density, the HDD has beenimproved to have a larger capacity, is used and will be used as anexternal memory device for use with consumer AV devices such asaudio-visual (AV) home server, in-vehicle device, etc.

The hard disk has been designed in the past to have a smaller andsmaller. For example, there has been proposed an HDD using a hard diskof 1.8 inches or 1 inch and intended for use in a mobile device such asdigital still camera (DSC), portable music player or the like.

On the other hand, the nonvolatile semiconductor memory represented bythe flash memory is advantageous in low power consumption, quickstart-up, high shock resistance, etc. and has a capacity of more than 1GB. Thus, the nonvolatile semiconductor memory is used in variousapplications with effective utilization of its advantages.

Note here that a small memory device for use in a mobile device shouldbe inexpensive, have a large capacity, be low in power consumption, beable to respond quickly and have further advantageous features.

However, the HDD can start up, namely, can get ready for write or readof data in a few seconds after energized. On the other hand, thenonvolatile semiconductor memory can instantaneously start up whenenergized. Namely, the moment the memory is energized, it will get readyfor data write or read.

Also, when the HDD is idling, namely, when it is in waiting state fordata write or read, it is consuming the power uselessly, which willadversely affect the power availability in an HDD-based mobile devicewhich uses a limited source of energy. Further, if any of the clusterson the track of the hard disk becomes defective, the data transfer ratewill be deteriorated because a normal cluster has to be substituted forthe defective one.

There has been proposed a hybrid storage device in which an HDD andnonvolatile semiconductor memory is combined to compensate for theproblems of the HDD with the advantages of the nonvolatile semiconductormemory. The Inventors has proposed various hybrid storage devices inwhich an HDD and nonvolatile semiconductor memory are managed by asingle file system as in the Japanese Patent Laid Open Nos. 2003-123379(will be referred to as “Patent Document 1” hereunder), 2003-125358(will be referred to as “Patent Document 2” hereunder), 2002-150699(will be referred to as “Patent Document 3” hereunder) and 2000-324435(will be referred to as “Patent Document 4” hereunder).

Note that necessary system data for access to software and data forcontrolling an HDD controller in an HDD is stored in a predeterminedarea of a hard disk and cannot be read unless the HDD starts up.Therefore, even after energized, the hybrid storage device cannot beused for a while until the system data is read from the hard disk. Onthis account, the Patent Document 1 proposes that the system data isstored in the nonvolatile semiconductor memory so that the hybridstorage device is operable immediately after energized.

Also the HDD takes a few seconds until it can record or reproduce data.That is, it cannot record or reproduce data to or from itself before itstarts up (reaches a predetermined velocity of rotation). The PatentDocument 2 proposes that for recording data, a leading portion of thedata for a predetermined length of time from the data top is written tothe nonvolatile semiconductor memory and the data portion following theleading portion is written to the HDD having been started up, while forreproducing the written data, the data written in the nonvolatilesemiconductor memory is read and the data written in the HDD started up,so that data can be recorded or reproduced immediately after the hybridstorage device is energized.

The Patent Document 3 proposes that the nonvolatile semiconductor memoryis used as a spare area for a defective sector as well to prevent thetransfer rate from being lowered.

In case an HDD is used in a video camera or the like, when power supplyto the HDD is suddenly interrupted because the video camera is droppedor applied with a shock with the result that no file system isregistered, data will not be reproducible. To avoid this, it isnecessary to periodically update the file system in a predetermined areain the HDD, which however will cause the recording speed to be loweredconsiderably. On this account, the Patent Document 4 proposes that anarea in which the file system to be updated is allocated to thenonvolatile semiconductor memory to protect data without lowering thetransfer rate.

The nonvolatile semiconductor memory being used only as a transient dataarea while the HDD is used in a steady state, a combination of thesmall-capacity nonvolatile semiconductor memory and large-capacity HDDprovides a low-cost, high-performance storage device.

Note here that in the hybrid storage device, it is important toefficiently utilize the small-capacity nonvolatile semiconductor memoryin order to assure that the hybrid storage data is inexpensive. If ahost device accessing the hybrid storage device writes data to the HDDarea and nonvolatile semiconductor memory area without differentiationbetween the areas, the nonvolatile semiconductor memory area will beconsumed to the full extent without making the most of its advantage.

It is possible that a DSC, potable music player, video camera or thelike as a host device accesses the hybrid storage device. The latest DSCand the like is connectable to a PC (personal computer), and the PC canread a content recorded in a storage medium incorporated in the DSC orwrite data to the storage medium. Also, a removable storage device towhich data has been recorded by the DSC can be connected to the PC, andthe PC can read or write data from or to the removable storage device.

However, since the general purpose device such as PC manages data on thebasis of a predetermined file system, so it cannot make recognitionbetween the nonvolatile semiconductor memory area and HDD area in thehybrid storage device. That is, since the general-purpose device such asPC can only recognize the hybrid storage device as one storage, it isadapted to start data record to the nonvolatile semiconductor memoryarea and record data to the HDD area when the nonvolatile semiconductormemory area becomes full of the recorded data or to record data to theHDD area after the HDD is started up and record data to the nonvolatilesemiconductor memory area when the HDD area becomes full of the recordeddata. Namely, the advantage of the hybrid storage device cannoteffectively be utilized.

DISCLOSURE OF THE INVENTION

It is therefore desirable to provide a composite memory device having anonvolatile semiconductor memory area and HDD area and to and from whichdata can be recorded and reproduced with effective utilization of theadvantage thereof, a method of writing data to the composite memorydevice and a program for writing data to the composite memory device.

According an embodiment of the present invention, there is provided acomposite memory device including:

a recording medium having a first data area assigned a first physicaladdress;

a nonvolatile recording medium having a second data area assigned asecond physical address, and an identification information tableassigned logical addresses for managing the first and second physicaladdresses and having predetermined identification information writtentherein at each of the logical addresses;

an interface to which a host device is to be connected;

a recognizing means for recognizing a host device connected to theinterface;

an identification information table reading means for reading theidentification information table from the nonvolatile recording medium;

an information selecting means for selecting a logical address where thepredetermined identification information is written on the basis of theresult of recognition supplied from the recognizing means andidentification information table read by the identification informationtable reading means;

a converting means for converting a logical address selected by theidentification information selecting means into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area;

a data allocating means for allocating data supplied from the hostdevice connected to the interface to the first or second data area onthe basis of the conversion made by the converting means;

a first wiring means for writing the data allocated to the first dataarea by the data allocating means at a predetermined location in thefirst data area on the basis of the first physical address; and

a second writing means for writing the data allocated to the second dataarea by the data allocating means on the basis of the second physicaladdress.

Also, according to another embodiment of the present invention, there isprovided a method of writing data to a composite memory device includinga recording medium having a first data area assigned a first physicaladdress, a nonvolatile recording medium having a second data areaassigned a second physical address, and an identification informationtable assigned logical addresses for managing the first and secondphysical addresses and having predetermined identification informationwritten therein at each of the logical addresses, and an interface towhich a host device is to be connected, the method including:

a recognizing step of recognizing a host device connected to theinterface;

an identification information table reading step of reading theidentification information table from the nonvolatile recording medium;

an information selecting step of selecting a logical address where thepredetermined identification information is written on the basis of theresult of recognition supplied from the recognizing step andidentification information table read in the identification informationtable reading step;

a converting step of converting a logical address selected in theidentification information selecting step into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area;

a data allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting step;

a first writing step of writing the data allocated to the first dataarea in the data allocating step at a predetermined location in thefirst data area on the basis of the first physical address; and

a second writing step of writing the data allocated to the second dataarea in the data allocating step on the basis of the second physicaladdress.

Also, according to another embodiment of the present invention, there isprovided a program for having a computer write data to a compositememory device including a recording medium having a first data areaassigned a first physical address, a nonvolatile recording medium havinga second data area assigned a second physical address, and anidentification information table assigned logical addresses for managingthe first and second physical addresses and having predeterminedidentification information written therein at each of the logicaladdresses, and an interface to which a host device is to be connected,the program including:

a recognizing step of recognizing a host device connected to theinterface;

an identification information table reading step of reading theidentification information table from the nonvolatile recording medium;

an information selecting step of selecting a logical address where thepredetermined identification information is written on the basis of theresult of recognition supplied from the recognizing step andidentification information table read in the identification informationtable reading step;

a converting step of converting a logical address selected in theidentification information selecting step into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area;

a data allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting step;

a first writing step of writing the data allocated to the first dataarea in the data allocating step at a predetermined location in thefirst data area on the basis of the first physical address; and

a second writing step of writing the data allocated to the second dataarea in the data allocating step on the basis of the second physicaladdress.

Also, according to another embodiment of the present invention, there isprovided a composite memory device including:

a recording medium having a first data area assigned a first physicaladdress;

a nonvolatile recording medium having a second data area assigned asecond physical address, and a first identification information tableassigned logical addresses for managing the first and second physicaladdresses and having written therein identification information thatdata write at the physical addresses is refused and a secondidentification information table assigned logical addressescorresponding to the second physical address and having predeterminedidentification is written at each of the logical addresses;

an interface to which a host device is to be connected;

a recognizing means for recognizing a host device connected to theinterface;

an identification information table reading means for reading the firstidentification information table or the first and second identificationinformation tables from the nonvolatile recording medium on the basis ofthe result of recognition supplied from the recognizing means;

an information selecting means for selecting a logical address where thepredetermined identification information is written on the basis of thefirst identification information table or the first and secondidentification information tables read by the identification informationtable reading means;

a converting means for converting a logical address selected by theidentification information selecting means into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area;

a data allocating means for allocating data supplied from the hostdevice connected to the interface to the first or second data area onthe basis of the conversion made by the converting means;

a first wiring means for writing the data allocated to the first dataarea by the data allocating means at a predetermined location in thefirst data area on the basis of the first physical address; and

a second writing means for writing the data allocated to the second dataarea by the data allocating means on the basis of the second physicaladdress.

Also, according to another embodiment of the present invention, there isprovided a method of writing data to a composite memory device includinga recording medium having a first data area assigned a first physicaladdress, a nonvolatile recording medium having a second data areaassigned a second physical address, and a first identificationinformation table assigned logical addresses for managing the first andsecond physical addresses and having written therein identificationinformation that data write at the physical addresses is refused and asecond identification information table assigned logical addressescorresponding to the second physical address and having predeterminedidentification is written at each of the logical addresses, and aninterface to which a host device is to be connected, the methodincluding:

a recognizing step of recognizing a host device connected to theinterface;

an identification information table reading step of reading the firstidentification information table or the first and second identificationinformation tables from the nonvolatile recording medium on the basis ofthe result of recognition supplied from the recognizing means;

an information selecting step of selecting a logical address where thepredetermined identification information is written on the basis of thefirst identification information table or the first and secondidentification information tables read in the identification informationtable reading step;

a converting step of converting a logical address selected in theidentification information selecting step into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area;

a data allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means;

a first wiring step of writing the data allocated to the first data areain the data allocating means at a predetermined location in the firstdata area on the basis of the first physical address; and

a second writing step of writing the data allocated to the second dataarea in the data allocating step on the basis of the second physicaladdress.

Also, according to another embodiment of the present invention, there isprovided a program for having a computer write data to a compositememory device including a recording medium having a first data areaassigned a first physical address, a nonvolatile recording medium havinga second data area assigned a second physical address, and a firstidentification information table assigned logical addresses for managingthe first and second physical addresses and having written thereinidentification information that data write at the physical addresses isrefused and a second identification information table assigned logicaladdresses corresponding to the second physical address and havingpredetermined identification is written at each of the logicaladdresses, and an interface to which a host device is to be connected,the program including:

a recognizing step of recognizing a host device connected to theinterface;

an identification information table reading step of reading the firstidentification information table or the first and second identificationinformation tables from the nonvolatile recording medium on the basis ofthe result of recognition supplied from the recognizing means;

an information selecting step of selecting a logical address where thepredetermined identification information is written on the basis of thefirst identification information table or the first and secondidentification information tables read in the identification informationtable reading step;

a converting step of converting a logical address selected in theidentification information selecting step into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area;

a data allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means;

a first wiring step of writing the data allocated to the first data areain the data allocating means at a predetermined location in the firstdata area on the basis of the first physical address; and

a second writing step of writing the data allocated to the second dataarea in the data allocating step on the basis of the second physicaladdress.

Also, according to another embodiment of the present invention, there isprovided a composite memory device including:

a recording medium having a first data area assigned a first physicaladdress;

a nonvolatile recording medium having a second data area assigned asecond physical address, a first identification information tableassigned a second data area assigned a second physical address andhaving predetermined identification information written at the firstlogical address and a second identification information table assigned asecond logical address corresponding to the second physical address andhaving predetermined identification information written at the secondlogical address;

an interface to which a host device is to be connected;

a recognizing means for recognizing a host device connected to theinterface;

an identification information table reading means for reading the firstand second identification information tables from the nonvolatilerecording medium on the basis of the result of recognition supplied fromthe recognizing means;

a first information selecting means for selecting the first logicaladdress where the predetermined identification information is writtenfrom the first identification information table read by theidentification information table reading means;

a second information selecting means for selecting the second logicaladdress where the predetermined identification information is writtenfrom the second identification information table read by theidentification information table reading means on the basis of theresult of recognition supplied from the recognizing means;

a conversion table generating means for generating a conversion table inwhich the first logical address selected by the first informationselecting means and second logical address selected by the secondinformation selecting means are associated with each other;

a converting means for converting the first logical address selected bythe first identification information selecting means into a firstpredetermined physical address corresponding to the first data area andthe second logical address selected by the second information selectingmeans into a second predetermined physical address corresponding to thesecond data area;

a data allocating means for allocating data supplied from the hostdevice connected to the interface to the first or second data area onthe basis of the conversion made by the converting means;

a first wiring means for writing the data allocated to the first dataarea by the data allocating means at a predetermined location in thefirst data area on the basis of the first physical address converted bythe converting means;

a second writing means for writing the data allocated to the second dataarea by the data allocating means at a predetermined location in thesecond data area on the basis of the second physical address convertedby the converting means; and

a third writing means for writing data written in the second data areaby the second writing means at a predetermined location in the firstdata area on the basis of the conversion table generated by theconversion table generating means.

Also, according to another embodiment of the present invention, there isprovided a method of writing data to a composite memory device includinga recording medium having a first data area assigned a first physicaladdress, a nonvolatile recording medium having a second data areaassigned a second physical address, a first identification informationtable having a second data area assigned a second physical address andhaving predetermined identification information written at the firstlogical address and a second identification information table assigned asecond logical address corresponding to the second physical address andhaving predetermined identification information written at the secondlogical address, and an interface to which a host device is to beconnected, the method including:

a recognizing step of recognizing a host device connected to theinterface;

an identification information table reading step of reading the firstand second identification information tables from the nonvolatilerecording medium on the basis of the result of recognition supplied fromthe recognizing step;

a first information selecting step of selecting the first logicaladdress where the predetermined identification information is writtenfrom the first identification information table read in theidentification information table reading step;

a second information selecting step of selecting the second logicaladdress where the predetermined identification information is writtenfrom the second identification information table read in theidentification information table reading step on the basis of the resultof recognition supplied from the recognizing step;

a conversion table generating step of generating a conversion table inwhich the first logical address selected in the first informationselecting step and second logical address selected by the secondinformation selecting means are associated with each other;

a converting step of converting the first logical address selected inthe first identification information selecting step into a firstpredetermined physical address corresponding to the first data area andthe second logical address selected in the second information selectingstep into a second predetermined physical address corresponding to thesecond data area;

a data allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means;

a first wiring step of writing the data allocated to the first data areain the data allocating step at a predetermined location in the firstdata area on the basis of the first physical address converted in theconverting step;

a second writing step of writing the data allocated to the second dataarea in the data allocating step at a predetermined location in thesecond data area on the basis of the second physical address convertedin the converting step; and

a third writing step of writing data written in the second data area inthe second writing step at a predetermined location in the first dataarea on the basis of the conversion table generated in the conversiontable generating step.

Also, according to another embodiment of the present invention, there isprovided a program for having a computer write to a composite memorydevice including a recording medium having a first data area assigned afirst physical address, a nonvolatile recording medium having a seconddata area assigned a second physical address, a first identificationinformation table having a second data area assigned a second physicaladdress and having predetermined identification information written atthe first logical address and a second identification information tablehaving a second logical address corresponding to the second physicaladdress and having predetermined identification information written atthe second logical address, and an interface to which a host device isto be connected, the method including:

a recognizing step of recognizing a host device connected to theinterface;

an identification information table reading step of reading the firstand second identification information tables from the nonvolatilerecording medium on the basis of the result of recognition supplied fromthe recognizing step;

a first information selecting step of selecting the first logicaladdress where the predetermined identification information is writtenfrom the first identification information table read in theidentification information table reading step;

a second information selecting step of selecting the second logicaladdress where the predetermined identification information is writtenfrom the second identification information table read in theidentification information table reading step on the basis of the resultof recognition supplied from the recognizing step;

a conversion table generating step of generating a conversion table inwhich the first logical address selected in the first informationselecting step and second logical address selected by the secondinformation selecting means are associated with each other;

a converting step of converting the first logical address selected inthe first identification information selecting step into a firstpredetermined physical address corresponding to the first data area andthe second logical address selected in the second information selectingstep into a second predetermined physical address corresponding to thesecond data area;

a data allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means;

a first wiring step of writing the data allocated to the first data areain the data allocating step at a predetermined location in the firstdata area on the basis of the first physical address converted in theconverting step;

a second writing step of writing the data allocated to the second dataarea in the data allocating step at a predetermined location in thesecond data area on the basis of the second physical address convertedin the converting step; and

a third writing step of writing data written in the second data area inthe second writing step at a predetermined location in the first dataarea on the basis of the conversion table generated in the conversiontable generating step.

In the composite memory device as one embodiment of the presentinvention, since the operation of data write to the data area is limitedaccording to the type of the host device, even in case data write ismade from a general-purpose device, no data write will be made to thedata area in the nonvolatile recording medium unless the entire dataarea in the recording medium is “already allocated”. Therefore, evenafter data write is made from the general-purpose device, the compositememory device permits a dedicated host device can write data to therecording medium low in bit cost and nonvolatile recording mediumadvantageous in quick response, low power consumption, etc. witheffective utilization of the advantages of these recording media.

Also in the data writing method and program as other embodiments of thepresent invention, since data is written to the composite memory devicethat limits the operation of data write to the data area according tothe type of the host device, in case a general-purpose host device isconnected to the composite memory device, no data write will be made tothe data area in the nonvolatile recording medium unless the entire dataarea in the recording medium is “already allocated”. Therefore, evenafter data write is made from the general-purpose device, each of themethod and program permits a dedicated host device to write data to therecording medium low in bit cost and nonvolatile recording mediumadvantageous in quick response, low power consumption, etc. witheffective utilization of the advantages of these recording media.

Also in the composite memory device as another embodiment of the presentinvention, since the operation of data write to the data area is limitedaccording to the type of the host device, in case data write is madefrom a general-purpose device, no data write will be made because it isinhibited to write data to the entire data area in the nonvolatilerecording medium. Therefore, even after data write is made from thegeneral-purpose device, the composite memory device permits a dedicatedhost device to write data to the recording medium low in bit cost andnonvolatile recording medium advantageous in quick response, low powerconsumption, etc. with effective utilization of the advantages of theserecording media.

Also in the data writing method and program as other embodiments of thepresent invention, since data is written to the composite memory devicethat limits the operation of data write to the data area according tothe type of the host device, in case data write is made from ageneral-purpose host device, no data write will be made to the data areain the nonvolatile recording medium because it is inhibited to writedata to the entire data area in the nonvolatile recording medium.Therefore, even after data write is made from the general-purposedevice, each of the method and program permits a dedicated host deviceto write data to the recording medium low in bit cost and nonvolatilerecording medium advantageous in quick response, low power consumption,etc. with effective utilization of the advantages of these recordingmedia.

Also, since the composite memory device as another embodiment of thepresent invention has an FAT open to external devices and which managesthe data area of the recording medium and an FAT used only in therecording medium and which manages the data area of the nonvolatilerecording medium, limits the data write to the data area according tothe type of a host device connected to the interface and copies datawritten in the data area of the nonvolatile recording medium to the dataarea in the recording medium after completion of the data write, so nogeneral-purpose host device can neither write nor read data to or fromthe data area of the recording medium. Even after data write is madefrom the general-purpose device, the composite memory device permits adedicated host device to write data to the recording medium low in bitcost and nonvolatile recording medium advantageous in quick response,low power consumption, etc. with effective utilization of the advantagesof these recording media.

Also, since each of the method and program as other embodiments of thepresent invention has an FAT open to external devices and which managesthe data area of the recording medium and an FAT used only in therecording medium and which manages the data area of the nonvolatilerecording medium, write data to the composite memory device which limitsthe data write to the data area according to the type of a host deviceconnected to the interface, so in case the host device connected to theinterface is a general-purpose one, no data is written to the data areaof the nonvolatile recording medium, while in case the connected hostdevice is a dedicated one, data is written to the nonvolatile recordingmedium and the written data is copied to the recording medium.Therefore, since no access to the data area of the nonvolatile recordingmedium is permitted for both data write and read in case ageneral-purpose host device is connected to the interface of thecomposite memory device, even after data write is made from thegeneral-purpose device, each of the method and program permits adedicated host device to write data to the recording medium low in bitcost and nonvolatile recording medium advantageous in quick response,low power consumption, etc. with effective utilization of the advantagesof these recording media.

The foregoing and other features, aspects and advantages of the presentinvention will be come apparent from the following detailed descriptionof embodiments of the present invention when taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the composite memory device as anembodiment of the present invention.

FIG. 2 is also a block diagram of an HDD included in the compositememory device shown in FIG. 1.

FIG. 3 is a block diagram of a memory unit included in the compositememory device shown in FIG. 1.

FIG. 4 shows the meaning of identification information.

FIG. 5 shows the configuration of a directory area.

FIG. 6 shows a first flow of operations made for writing data suppliedfrom a host device to the composite memory device.

FIG. 7 shows a second flow of operations made for writing data suppliedfrom the host device to the composite memory device.

FIG. 8 shows a first configuration of a data area A and data area B.

FIG. 9 shows a second configuration of the data area A and data area B.

FIG. 10 shows a third flow of operations made for writing data suppliedfrom the host device to the composite memory device.

FIG. 11 shows a fourth flow of operations made for writing data suppliedfrom the host device to the composite memory device.

FIGS. 12A and 12B show a third configuration of the data area A and dataarea B.

FIG. 13 shows a fifth flow of operations made for writing data suppliedfrom the host device to the composite memory device.

FIG. 14 shows a sixth flow of operations made for writing data suppliedfrom the host device to the composite memory device.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is directed to a composite memory device includinga hard disk drive (HDD) having a disk-shaped recording medium installedtherein and a nonvolatile recording medium such as flash memory or thelike and in which a data area of the HDD and data area of thenonvolatile recording medium are handled as an integral area on thebasis of a predetermined file system. It should be noted that an examplein which an MS-DOS-compatible FAT (File Allocation Table) file system isadopted as the file system will be explained below.

As shown in FIG. 1, the composite memory device, generally indicatedwith a reference numeral 1, includes an HDD 10 having installed thereina recording medium 2 having a data area A in which an address (whichaddress will be referred to as “physical address” hereunder) is assignedto data having at least a predetermined size, a memory unit 11 includinga nonvolatile recording medium 3 having a data area B in which a seriesof addresses starting with the top address in the data area A isassigned to each data having a predetermined size and identificationinformation tables each having predetermined identification informationwritten at each memory predetermined address (will be referred to as“logical address” hereunder) therein, a device recognition unit 13 torecognize a host device 4, a processing unit 14 to read theidentification information table from the nonvolatile recording medium 3and select a logical address where predetermined identificationinformation is written on the base of the result of the recognition madeby the device recognition unit 13, a converter 15 to convert a logicaladdress selected by the processing unit 14 into a physical addresscorresponding to the data area A or into a memory address correspondingto the data area B, on the basis of a predetermined one of theidentification information tables, and data allocator 16 to assign datasupplied from the host device 4 to HDD 10 or memory unit 11 on the basisof the physical address or memory address resulted from the conversionmade in the converter 15. The composite memory device (will be referredto simply as “device” wherever appropriate hereunder) 1 is connected tothe host device 4 such as a dedicated or general-purpose one via aninterface 12 complying with any one of the standards IDE, SCSI, FC orUSB.

Note that the data areas A and B will be described in detail later withreference to FIGS. 8, 9 and 12.

Also note that the “dedicated host device” is an application device suchas video camera, digital camera, music player or the like, capable ofrecording and reproducing data efficiently on the basis of the advantageof the composite memory device 1. It is, for example, a device capableof issuing, when put into operation, an Identify Device Command (as inthe ATA standard) to the device 1 and acquiring parameter information onthe device 1, to thereby recognizing easily that the device 1 is acombination of the recording medium 2 and nonvolatile recording medium3. It should be noted that in this embodiment, the “dedicated hostdevice” can recognize the device 1, that is, can make differentiationbetween the HDD 10 and memory unit 11, which will be described in detaillater.

On the other hand, the “general-purpose” host device is a device capableof recording and reproducing data on the basis of a peculiar filesystem, such as personal computer. The general-purpose host devicecannot accurately recognize a memory device having a configuration notdefined in the file system. It should be noted that in this embodiment,the “general-purpose host device” can recognize the composite memorydevice 1 as a single data area without being able to recognize thedevice 1, that is, make differentiation between the HDD 10 and memoryunit 11.

As shown in FIG. 2, the HDD 10 includes a read/write head 20 to writedata to the recording medium 2 and read data from the recording medium2, a drive unit 21 to rotate the recording medium 2 at a predeterminedvelocity in a predetermination direction, a servo controller 22 tocontrol the head 20 and drive unit 21, a read/write channel unit 23 toprocess supplied data in a predetermined manner, a buffer memory 24 toprovisionally save data, an HDD controller 25 to control the servocontroller 22 and read/write channel unit 23, a processor (CPU) 26 thatmakes a predetermination computation to set a necessary command andparameter for operation of the servo controller 22, read/write channelunit 23, etc., and the recording medium 2 to which data is written andfrom which data is read.

The servo controller 22 controls the drive unit 21 to rotate therecording medium 2 at a predetermined velocity in a predetermineddirection, and also controls the driving of the read/write head 20 foraccess to a predetermined location in the recording medium 2,corresponding to a physical address supplied from the converter 15.

The read/write channel unit 23 operates, at the time of data writing, toencode (modulate) data supplied from the data allocator 16 and convertthe encoded data into a digital bit string matching the characteristicof the recording/reproduction system, and then supply the converted datato the head 20. Also, the read/write channel unit 23 operates, at thetime of data reading, to remove a high-frequency noise from a readsignal supplied from the head 20 and then digitize the read signal by ananalog-digital converter (ADC), process the digital signal by themaximum likelihood decoding or the like, and then demodulate the decodedsignal.

The buffer memory 24 is controlled by the HDD controller 25, at the timeof data writing, to provisionally save data supplied from the hostdevice 4 via the data allocator 16. When the data amount in the buffermemory 24 has reached a predetermined one, data is read from the buffermemory 24 and the read data is supplied to the read/write channel unit23. Also, the buffer memory 24 is controlled by the HDD controller 25,at the time of data reading, to provisionally save data supplied fromthe read/write channel unit 23. When the data amount in the buffermemory 24 has reached the predetermined one, data is read from thebuffer memory 24 and the read data is supplied to the host device 4 viathe data allocator 16 and interface 12. Also, the buffer memory 24operates, at the time of data reading and writing, to provisionally savedata. Thus, it is prevented from being deteriorated in performance dueto a difference in transfer rate between data.

The HDD controller 25 manages data transfer between the buffer memory 24and read/write channel unit 23 and between the buffer memory 24 and dataallocator 16 on the basis of the FAT file system which will be describedin detail later, and processes the data with respect to a format. Also,the HDD controller 25 processes the data with respect to encoding, errordetection and error correction with an error correction code during theformat elated data processing.

Also, the recording medium 2 is a disk-shaped one, and has the data areaA managed on the basis of the FAT system and in which a physical addressis assigned to data having each predetermined size depending upon anintended data format.

As shown in FIG. 3, the memory unit 11 includes the nonvolatilerecording medium 3 and a read/write unit 30 that writes data suppliedfrom the data allocator 16 to the nonvolatile recording medium 3 andreads data from the nonvolatile recording medium 3, on the basis of amemory address converted by the converter 15.

The nonvolatile recording medium 3 is, for example, a NAND type flashmemory card (memory stick, compact flash, SD card or the like) adoptingthe FAT file system, and has the data area B in which a series ofaddresses (memory addresses) starting with the top address in the dataarea A of the recording medium 2 is assigned to each data having apredetermined size and identification information tables each havingpredetermined identification information written at each predeterminedmemory address.

In this embodiment, the data area A in the recording medium 2 and dataarea in the nonvolatile recording medium 3 are integrated based on theFAT (File Allocation Table) file system and managed as an integral dataarea.

Here will be explained the FAT file system. The “FAT” is a table showinghow a file is stored in a cluster, and provides a format system tomanage the host device 4 on the basis of this table. The “formatting” isa process of zoning and rearranging a data memory area by areas eachhaving a predetermined size and assigning a number (physical address) toeach of the zoned and rearranged areas. The formatting consists of aso-called physical formatting in which a track formed on the recordingmedium 2 is divided into areas called “sectors”, and a so-called logicalformatting in which a plurality of the sectors is organized as a unitcalled “cluster” to define a system area C, disk area and data area.

Also, one sector is a minimum unit (normally of 512 bytes) for recordingdata in the recording medium 2. The present invention also adopts thesector as the minimum unit for data recording. The host device 4 uses alogical block address (LBA) to access the recording medium 2. Also, inthe FAT file system to manage the files, a plurality of sectors (Nsectors) is taken as one cluster and one cluster is taken as a minimumunit for write and read of data.

The system area C generated according to the format includes a FAT areain which a master boot record and FAT are written. The master bootrecord is a sector at an address LBA “0” as viewed from the host device4 and has a bootstrap code and partition table recorded therein.

As shown in FIG. 4, in the FTA, predetermined information such asinformation on the availability of the data area is indicated withidentification information. For example, identification information“0000h” indicates that a corresponding cluster is “blank”. Information“0002h to FFF6h” indicates that a corresponding cluster is “alreadyallocated”, and a corresponding value indicate a number of a nextcluster. Identification information “FFF7h” indicates that acorresponding cluster is “defective”. Identification information “FFF8hto FFFFh” indicate an end of file (EOF) at which a corresponding clusteris “already allocated”.

The data area includes a directory area in which information in a fileis managed, and a data area in which actual data is written. Thedirectory area includes information on a file name, extension,attribute, latest time of updating, starting-cluster address, file size,etc. of each directory (file) as shown in FIG. 5.

In this embodiment, the system area C to be read first when thecomposite memory device 1 is energized is set in the nonvolatilerecording medium 3 to which instantaneous data access is possible, notin the HDD 10 that takes a predetermined time from the energization ofthe device 1 until data access is enabled.

Therefore, the recording medium 2 in the HDD 10 has the data area A inwhich a physical address is assigned to each data having a predeterminedsize, while the nonvolatile recording medium 3 in the memory unit 11 hasthe data area B in which a memory address is assigned to each datahaving a predetermined size and the system area C including the FAT inwhich logical addresses are associated with the physical addresses inthe data area A and memory addresses in the data area B.

Therefore, the system area C can be accessed just after the compositememory device 1 connected to the host device 4 is turned on.

The device recognition unit 13 recognizes whether the host device 4connected to the interface 12 is a dedicated unit capable of makingdifferentiation between the HDD 10 and memory unit 11 or ageneral-purpose unit not capable of making differentiation between theHDD 10 and memory unit 11. The device recognition unit 13 supplies theresult of recognition to the processing unit 14.

The processing unit 14 includes a CPU making a computation and a RAM(random-access memory) used for provisionally saving data. It reads theFAT from the system area C stored in the nonvolatile recording medium 3,moves a selection pointer in the read FAT correspondingly to therecognition result supplied from the device recognition unit 13, andselects a logical address where predetermined identification informationis written. The processing unit 14 supplies the selected logical addressto the converter 15.

The converter 15 has an address conversion table on the basis of whichthe logical address supplied from the processing unit 14 is to beconverted into a physical or memory address on the basis of the logicaladdress. When the converted address is a physical address, the converter15 supplies the physical address to the HDD 10. When the convertedaddress is a memory address, the converter 15 supplies the memoryaddress to the memory unit 11. Also, the converter 15 supplies theresult of conversion to the data allocator 16.

Based on the conversion result supplied from the converter 15, the dataallocator 16 allocates data supplied from the host device 4 via theinterface 12 to the HDD 10 or memory unit 11. For example, in case thedata allocator 16 is supplied, from the converter 15, with informationthat the logical address has been converted into a physical address, itallocates data supplied from the host device 4 via the interface 12 tothe HDD 10. On the other hand, in case the data allocator 16 issupplied, from the converter 15, with information that the logicaladdress has been converted into a memory address, it allocates datasupplied from the host device 4 via the interface 12 to the memory unit11.

Here will be explained a first embodiment of the present invention withreference to the flow diagrams shown in FIGS. 6 and 7. It should benoted that as shown in FIG. 8, the composite memory device 1 as thefirst embodiment includes the recording medium 2 having the data area Aassigned physical addresses “0002h” to “7FFFh” and the nonvolatilerecording medium 3 having the data area B assigned memory addresses“8000h” to “8FFFh” and system area C including a predetermined FAT.

Also, to handle the data areas A and B integrally with each other, theFAT has assigned thereto logical addresses “0000h” to “7FFFh”corresponding to the data area A and logical addresses “8000h” to“8FFFh” corresponding to the data area B for connection to the data areaA. Therefore, in case data is written according to the FAT, when theentire data area A is “already allocated”, data will be written to thedata area B.

Also, when one sector defined based on a format has a capacity of 512bytes and 64 such sectors form one cluster, one cluster has a capacityof 64×512 bytes≈32 kB and the data area B in the recording medium 2 hasa data capacity of 32 kB×32767≈1 GB. Also, the capacity of the data areaB in the nonvolatile recording medium 3 is equivalent to 4096 clusters,namely, 32 kV×4096≈128 MB.

FIG. 8 also shows how a file (File 1) supplied from the host device 4 isdivided by cluster and written to the data area A. When reading suchfile, data written in the directory area is searched for a file name,data corresponding to a file name “File 1” is read, a logical addressindicating the top of a first cluster is extracted from the read data,and data corresponding to the file name “File 1” are sequentially readfrom the data area Bon the basis of the logical address and withreference to the FAT, to thereby read data.

Also, in the composite memory device 1, when the host device 4 isconnected to the interface 12, the device recognition unit 13 recognizeswhich the host device 4 is, a dedicated one or a general-purpose one,and data write is controlled by the processing unit 14 correspondinglyto the result of recognition. When a dedicated host device is connectedto the interface 12, data is written to the device 1 as in the flowdiagram in FIG. 6. On the other hand, when a general-purpose host deviceis connected to the interface 12, data is written to the device 1 as inthe flow diagram in FIG. 7.

Here will be explained data write to the composite memory device 1having a dedicated host device connected to the interface 12 thereof.

In step ST1, the composite memory device 1 judges whether it gets readyfor data write to the data area A. In case the result of judgement isaffirmative, the device 1 goes to step ST2. On the contrary, if theresult of judgement is negative, the device 1 goes to step ST7.

The recording medium 2 starts being rotated by the drive unit 21 underthe control of the servo controller 22 as above. It takes a few secondsuntil the rotation of the recording medium 2 reaches a predeterminedvelocity, namely, until the recording medium 2 gets ready for data.Therefore, the composite memory device 1 controls the data allocator 16to write data supplied from the dedicated host device to the data area Bin the nonvolatile recording medium 3 until the device 1 becomes readyfor data write to the data area A. When the device 1 becomes ready forthe data write to the data area A, it controls the data allocator 16 towrite data supplied from the dedicated host device to the data area A inthe recording medium 2.

In step ST2, the composite memory device 1 detects a blank cluster inthe data area B by searching the latter from the top. The processingunit 14 reads the FAT from the data area B, and deploys the read FAT inthe RAM. The processing unit 14 recognizes, based on the recognitionresult supplied from the device recognition unit 13, that the hostdevice 4 is a dedicated one, moves the selection pointer to a logicaladdress “8000h” in the FAT deployed in the RAM, and searches logicaladdresses “8000h” to “8FFFh” for identification information indicativeof a blank area with the selection pointer being moved in thatdirection.

In step ST3, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST4, the composite memory device 1 writes data to a data areacorresponding to a predetermined memory address in the data area B. Theconverter 15 converts the logical address supplied from the processingunit 14 into a memory address on the basis of the address conversiontable, and supplies the converted memory address to the memory unit 11.Also, the converter 15 informs the data allocator 16 that it hasconverted the logical address supplied from the processing unit 14 intothe memory address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the memory unit 11.The memory unit 11 will write data supplied from the data allocator 16to the data area B for the transferred-word length on the basis of thememory address supplied from the converter 15.

In step ST5, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area B.

In step ST6, the composite memory device 1 judges whether it should exitthe data writing process. In case the device 1 has decided to exit thedata writing process, it goes to step ST12. On the contrary, if thedevice 1 has decided to continuously write data, it goes back to stepST1. It should be noted that if the device 1 returns to step ST1 andfinds that it is not ready for data write to the data area A, it willrepeat the operations in steps ST2 to ST5 above.

In step ST7, the composite memory device 1 searches the data area A fromthe top thereof for a blank cluster. The processing unit 14 moves theselection pointer to a logical address “0002h” in the FAT deployed inthe RAM, and searches logical addresses “0002h” to “8FFFh” foridentification information indicative of a blank area with the selectionpointer being moved in that direction.

Note that the processing unit 14 may be informed, from a monitor unit(not shown) to monitor the started state of the recording medium 2, thatthe composite memory device 1 is ready for data write to the data area Aand go to step ST7.

In step ST8, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for writing, and supplies them tothe converter 15.

In step ST9, the device 1, the composite memory device 1 writes data toa data area corresponding to a predetermined physical address in thedata area A. The converter 15 converts the logical address supplied fromthe processing unit 14 into a physical address on the basis of theaddress conversion table, and supplies the converted physical address tothe HDD 10. Also, the converter 15 informs the data allocator 16 that ithas converted the logical address supplied from the processing unit 14into the physical address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the HDD 10. The HDD10 will write data supplied from the data allocator 16 to the data areaA for the transferred-word length on the basis of the physical addresssupplied from the converter 15.

In step ST10, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area B.

In step ST11, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST 12. On the contrary, if thedevice 1 has decided to continuously write data, it will go back to stepST7 and repeat the operations in steps ST8 to ST11 above.

In step ST12, the composite memory device 1 updates the FAT anddirectory correspondingly to the new data written to the data area B bygoing through steps ST2 to ST4 and new data written to the data area Aby going through steps ST7 to ST9.

Since data written to the composite memory device 1 will be read in thefirst-in first-out order, leading data in each file, if any, written tothe data area A cannot be read before the recording medium 2 put intorotation reaches a predetermined velocity for data reading. On thisaccount, the device 1 may be adapted to automatically write datasupplied from the dedicated host device to the data area B for apredetermined length of time, that is, for a time taken for therecording medium 2 to reach the predetermined velocity, irrespectivelyof whether the device 1 is ready for data write to the data area A.Owing to this adaptation, the device 1 can read the leading data in eachfile from the data area B, put the recording medium 2 into rotationwhile the leading data is being read and thus read data associated withthe leading data from the data area A in the recording medium 2 havingreached the predetermined velocity. So, data can be reproducedinstantaneously without the necessity of setting any wait time for thedata reproduction.

Next, the data write to the composite memory device 1 having ageneral-purpose host device connected to the interface 12 thereof willbe explained with reference to the flow diagram in FIG. 7.

In step ST20, the composite memory device 1 detects a blank cluster bysearching the data area A from the top of the latter after being readyfor data write to the data area A.

The processing unit 14 reads the FAT from the data area B, and deploysthe read FAT in the RAM. The processing unit 14 moves the selectionpointer to a logical address “0002h” in the FAT deployed in the RAM, andsearches logical addresses “0002h” to “8FFFh” for identificationinformation indicative of a blank area with the selection pointer beingmoved in that direction.

In step ST21, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST22, the composite memory device 1 writes data to a data areacorresponding to a predetermined physical address in the data area A.The converter 15 converts the logical address supplied from theprocessing unit 14 into a physical address on the basis of the addressconversion table, and supplies the converted physical address to the HDD10. Also, the converter 15 informs the data allocator 16 that it hasconverted the logical address supplied from the processing unit 14 intothe physical address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the HDD 10. The HDD10 will write data supplied from the data allocator 16 to the data areaA for the transferred-word length on the basis of the physical addresssupplied from the converter 15.

In step ST23, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area A.

In step ST24, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST25. On the contrary, if thedevice 1 has decided to continuously write data, it goes back to stepST20 and repeats the operations in steps ST20 to ST24 above.

In step ST25, the composite memory device 1 updates the FAT anddirectory correspondingly to the new data written to the data area A.

Note that steps ST1 to ST12 and steps ST20 to ST25 may be programmed andthese programs be executed to let the composite memory device 1 to makethe aforementioned data write.

Therefore, since the data area B in the nonvolatile recording medium 3is allocated after the data area A as above, the data write to the dataarea B from the dedicated host device will not be done before the dataarea A as a whole is “already allocated”.

Since the composite memory device 1 limits the operation of data writeto the data area according to the type of the host device 4 as above,even in case data write is made from a general-purpose device, no datawrite will be made to the data area A before the entire data area B is“already allocated”. Therefore, even after data write is made from thegeneral-purpose device, the device 1 as the embodiment of the presentinvention can write data to the recording medium 2 low in bit cost andnonvolatile recording medium 3 advantageous in quick response, low powerconsumption, etc. from a dedicated host device with effectiveutilization of the advantages of these recording media 2 and 3.

Also, with the composite memory device 1 as the embodiment of thepresent invention, even a general-purpose host device 4 connected to theinterface 12 can read data, for reproduction, by tracking information,associated with the data, in the FAT stored in the data area B, it canread data having been written from a dedicated host device and thelatter can read data having been written from the general-purpose hostdevice.

Next, a second embodiment of the composite memory device according tothe present invention will be illustrated and explained. In the secondembodiment, when the host device 4 is a general-purpose one, it isinhibited from writing data to the data area B. On the contrary, whenthe host device 4 is a dedicated one, it is allowed as usual to writedata to the data area B as well.

The composite memory device 1 as the second embodiment includes therecording medium 2 having a data area A assigned physical addresses“0000h” to “7FFFh”, nonvolatile recording medium 3 having a data area Bassigned memory addresses “8000h” to “8FFFh”, and the system area Cincluding first and second FATs.

As shown in FIG. 9A, the first FAT has assigned thereto logicaladdresses “0000h” to “7FFFh” corresponding to the data area A andlogical addresses “8000h” to “8FFFh” corresponding to the data area B atthe time of initialization or shipment from the factory, and has writtentherein, written therein at the time of initialization or shipment fromthe factory, identification information indicating that it is inhibitedto write data at the logical addresses “8000h” to “8FFFh”, for example,identification information indicating that data has been written in thedata areas, identification information (9000h to FFFFh) indicating thatdata have been written outside the data areas, identificationinformation (FFF8h to FFFFh) indicating an EOF (end of file) oridentification information (FFF7h) indicating that an intended clusteris defective.

As shown in FIG. 9B, the second FAT has assigned thereto addresses“8000h” to “8FFFh” corresponding to the data area B at the time ofinitialization or shipment from the factory.

Here will be explained data write to the composite memory device 1having a dedicated host device connected to the interface 12 thereofwith reference to the flow diagram in FIG. 10.

In step ST30, the composite memory device 1 judges whether it is readyfor data write to the data area A. In case the result of judgement isnegative, the device 1 goes to step ST31. On the contrary, if the resultof judgement is affirmative, the device 1 goes to step ST36.

The recording medium 2 starts being rotated by the drive unit 21 underthe control of the servo controller 22. It takes a few seconds until therotation of the recording medium 2 reaches a predetermined velocity,namely, until the recording medium 2 gets ready for data write.Therefore, the composite memory device 1 controls the data allocator 16to write data supplied from the dedicated host device to the data area Bin the nonvolatile recording medium 3 until the device 1 becomes readyfor data write to the data area A. When the device 1 becomes ready forthe data write to the data area A, it controls the data allocator 16 towrite data supplied from the dedicated host device to the data area A inthe recording medium 2.

In step ST31, the composite memory device 1 detects a blank cluster inthe data area B by searching the latter from the top. The processingunit 14 reads the first and second FATs from the data area B, anddeploys the read first and second FATs in the RAM. The processing unit14 recognizes, based on the recognition result supplied from the devicerecognition unit 13, that the host device 4 is a dedicated one, movesthe selection pointer to a logical address “8000h” in the second FATdeployed in the RAM, and searches logical addresses “8000h” to “8FFFh”for identification information indicative of a blank area with theselection pointer being moved in that direction.

In step ST32, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST33, the composite memory device 1 writes data to a data areacorresponding to a predetermined memory address in the data area B. Theconverter 15 converts the logical address supplied from the processingunit 14 into a memory address on the basis of the address conversiontable, and supplies the converted memory address to the memory unit 11.Also, the converter 15 informs the data allocator 16 that it hasconverted the logical address supplied from the processing unit 14 intothe memory address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the memory unit 11.The memory unit 11 will write data supplied from the data allocator 16to the data area B for the transferred-word length on the basis of thememory address supplied from the converter 15.

In step ST34, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area B.

In step ST35, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST41. On the contrary, if thedevice 1 has decided to continuously write data, it goes back to stepST30. It should be noted that if the device 1 returns to step ST30 andfinds that it is not ready for data write to the data area A, it willrepeat the operations in steps ST31 to ST34 above.

In step ST36, the composite memory device 1 searches the data area Afrom the top thereof for a blank cluster. The processing unit 14 movesthe selection pointer to a logical address “0002h” in the first FATdeployed in the RAM, and searches logical addresses “0002h” to “8FFFh”for identification information indicative of a blank area with theselection pointer being moved in that direction.

Note that the processing unit 14 may be informed, from a monitor unit(not shown) to monitor the started state of the recording medium 2, thatthe composite memory device 1 is ready for data write to the data area.A and go to step ST36.

In step ST37, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST38, the device 1, the composite memory device 1 writes data toa data area corresponding to a predetermined physical address in thedata area A. The converter 15 converts the logical address supplied fromthe processing unit 14 into a physical address on the basis of theaddress conversion table, and supplies the converted physical address tothe HDD 10. Also, the converter 15 informs the data allocator 16 that ithas converted the logical address supplied from the processing unit 14into the physical address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the HDD 10. The HDD10 will write data supplied from the data allocator 16 to the data areaA for the transferred-word length on the basis of the physical addresssupplied from the converter 15.

In step ST39, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area B.

In step ST40, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST41. On the contrary, if thedevice 1 has decided to continuously write data, it will go back to stepST36 and repeat the operations in steps ST37 to ST40 above.

In step ST41, the composite memory device 1 updates the first and secondFATs and directory correspondingly to the new data written to the dataarea B by going through steps ST31 to ST33 and new data written to thedata area A by going through steps ST36 to ST38.

Note that at the time of updating the first FAT, the identificationinformation having been written at a logical address corresponding tothe data area B at the time of initialization or shipment from thefactory to indicate that data write is inhibited is updated with thesame identification information (actual identification information) asthe new identification information written at the logical address of thesecond FAT. Therefore, the second FAT is connected to the data area A,and also connected within the data area B. Also, the second FAT isregistered as a defective cluster and also as an EOF at the completionof data write.

Since data written to the composite memory device 1 will be read in thefirst-in first-out order, leading data in each file, if any, written tothe data area A cannot be read before the recording medium 2 put intorotation reaches a predetermined velocity for data reading. On thisaccount, the device 1 may be adapted to automatically write datasupplied from the dedicated host device to the data area B for apredetermined length of time, that is, for a time taken for therecording medium 2 to reach the predetermined velocity, irrespectivelyof whether the device 1 is ready for data write to the data area A.Owing to this adaptation, the device 1 can read the leading data in eachfile from the data area B, put the recording medium 2 into rotationwhile the leading data is being read and thus read data associated withthe leading data from the data area A in the recording medium 2 havingreached the predetermined velocity. So, data can be reproducedinstantaneously without the necessity of setting any wait time for thedata reproduction.

Next, the data write to the composite memory device 1 having ageneral-purpose host device connected to the interface 12 thereof willbe explained with reference to the flow diagram in FIG. 11.

In step ST50, the composite memory device 1 detects a blank cluster bysearching the data area A from the top of the latter after being readyfor data write to the data area A.

The processing unit 14 reads the first FAT from the data area B, anddeploys the read first FAT in the RAM. The processing unit 14 moves theselection pointer to a logical address “0002h” in the first FAT deployedin the RAM, and searches logical addresses “0002h” to “8FFFh” foridentification information indicative of a blank area with the selectionpointer being moved in that direction. It should be noted that sinceidentification information that data write is inhibited is written atthe logical addresses “8000h” to “8FFFh”, the processing unit 14 willnot be able to write new data in case identification informationindicating “already written” is written at the logical addresses “0000h”to “7FFFh”.

In step ST51, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST52, the composite memory device 1 writes data to a data areacorresponding to a predetermined physical address in the data area A.The converter 15 converts the logical address supplied from theprocessing unit 14 into a physical address on the basis of the addressconversion table, and supplies the converted physical address to the HDD10. Also, the converter 15 informs the data allocator 16 that it hasconverted the logical address supplied from the processing unit 14 intothe physical address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the HDD 10. The HDD10 will write data supplied from the data allocator 16 to the data areaA for the transferred-word length on the basis of the physical addresssupplied from the converter 15.

In step ST53, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area A.

In step ST54, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST55. On the contrary, if thedevice 1 has decided to continuously write data, it goes back to stepST50 and repeats the operations in steps ST50 to ST54 above.

In step ST55, the composite memory device 1 updates the first FAT anddirectory correspondingly to the new data written to the data area A.

Note that steps ST30 to ST41 and steps ST50 to ST55 may be programmedand these programs be executed to let the composite memory device 1 tomake the aforementioned data write.

Since the composite memory device 1 limits the operation of data writeto the data area according to the type of the host device 4 as above, incase data write is made from a general-purpose device, no data writewill be made to the data area A because data write to the entire dataarea B is inhibited. Therefore, even after data write is made from thegeneral-purpose device, the device 1 as the embodiment of the presentinvention can write data to the recording medium 2 low in bit cost andnonvolatile recording medium 3 advantageous in quick response, low powerconsumption, etc. from a dedicated host device with effectiveutilization of the advantages of these recording media 2 and 3.

Also, with the composite memory device 1 as the embodiment of thepresent invention, even a general-purpose host device 4 connected to theinterface 12 can read data, for reproduction, by tracking information,associated with the data, in the first FAT stored in the data area B, itcan read data having been written from a dedicated host device and thelatter can read data having been written from the general-purpose hostdevice.

Next, a third embodiment of the composite memory device according to thepresent invention will be illustrated and explained.

In this third embodiment, when a general-purpose host device 4 is towrite data to the composite memory device as the third embodiment, it isinhibited from writing data to the data area B, while a dedicated hostdevice 4 is allowed as usual to write data to the data area B as well.It should be noted that in the third embodiment, the data area B is usedfor provisionally saving data supplied from a dedicated host device.

The composite memory device 1 as the third embodiment includes therecording medium 2 having a data area A assigned predetermined physicaladdresses and nonvolatile recording medium 3 having a data area Bassigned predetermined memory addresses and the system area C includingthird and fourth FATs.

The third FAT has assigned thereto predetermined logical addressescorresponding to the data area A as shown in FIG. 12A, and the fourthFAT has assigned thereto predetermined logical addresses correspondingto the data area B as shown in FIG. 12B.

Here will be explained data write to the composite memory device 1having a dedicated host device connected to the interface 12 thereofwith reference to the flow diagram in FIG. 13.

In step ST60, the composite memory device 1 judges whether it is readyfor data write to the data area A. In case the result of judgement isnegative, the device 1 goes to step ST61. On the contrary, if the resultof judgement is affirmative, the device 1 goes to step ST67.

The recording medium 2 starts being rotated by the drive unit 21 underthe control of the servo controller 22. It takes a few seconds until therotation of the recording medium 2 reaches a predetermined velocity,namely, until the recording medium 2 gets ready for data write.Therefore, the composite memory device 1 controls the data allocator 16to write data supplied from the dedicated host device to the data area Bin the nonvolatile recording medium 3 until the device 1 becomes readyfor data write to the data area A. When the device 1 becomes ready forthe data write to the data area A, it controls the data allocator 16 towrite data supplied from the dedicated host device to the data area A inthe recording medium 2.

In step ST61, the composite memory device 1 detects a blank cluster inthe data area A by searching the latter from the top. The processingunit 14 reads the third FAT from the data area B, and deploys the readthird FAT in the RAM. The processing unit 14 moves the selection pointerto a predetermined logical address in the second FAT deployed in theRAM, and searches logical addresses including from the predetermined oneto the end one for identification information indicative of a blank areawith the selection pointer being moved in that direction.

In step ST62, the composite memory device 1 detects a blank cluster bysearching the data area B from the top of the latter. Further, theprocessing unit 14 reads the fourth FAT from the data area B and deploysthe read fourth FAT in the RAM. The processing unit 14 recognizes, basedon the result of recognition supplied from the device recognition unit13, that the host device 4 is a dedicated one, moves the selectionpointer to predetermined logical addresses of the third and fourth FATsdeployed in the RAM and searches logical addresses including from thepredetermined one to the end one for identification informationindicative of a blank area with the selection pointer being moved inthat direction. The processing unit 14 generates a conversion table inwhich a logical address indicating a blank area in the third FAT isassociated with a logical address indicating a blank area in the fourthFAT. The generated conversion table is stored into a predetermined areain the data area B.

In step ST63, the processing unit 14 generates a logical address of aposition for starting data write to the blank area detected in thefourth FAT, length of data to be transferred and a command for datawriting operation, and supplies them to the converter 15.

In step ST64, the composite memory device 1 writes data to a data areacorresponding to a predetermined memory address in the data area B. Theconverter 15 converts the logical address supplied from the processingunit 14 into a memory address on the basis of the address conversiontable, and supplies the converted memory address to the memory unit 11.Also, the converter 15 informs the data allocator 16 that it hasconverted the logical address supplied from the processing unit 14 intothe memory address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the memory unit 11.The memory unit 11 will write data supplied from the data allocator 16to the data area B for the transferred-word length on the basis of thememory address supplied from the converter 15.

In step ST65, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area B.

In step ST66, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST72. On the contrary, if thedevice 1 has decided to continuously write data, it goes back to stepST60. It should be noted that if the device 1 returns to step ST60 andfinds that it is not ready for data write to the data area A, it willrepeat the operations in steps ST61 to ST65 above.

In step ST67, the composite memory device 1 detects a blank cluster bysearching the data area A from the top thereof. The processing unit 14moves the selection pointer to a predetermined logical address in thethird FAT deployed in the RAM, and searches logical addresses includingfrom the predetermined one to the end one for identification informationindicative of a blank area with the selection pointer being moved inthat direction.

Note that the processing unit 14 may be informed, from a monitor unit(not shown) to monitor the started state of the recording medium 2, thatthe composite memory device 1 is ready for data write to the data area Aand go to step ST67.

In step ST68, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST69, the device 1, the composite memory device 1 writes data toa data area corresponding to a predetermined physical address in thedata area A. The converter 15 converts the logical address supplied fromthe processing unit 14 into a physical address on the basis of theaddress conversion table, and supplies the converted physical address tothe HDD 10. Also, the converter 15 informs the data allocator 16 that ithas converted the logical address supplied from the processing unit 14into the physical address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the HDD 10. The HDD10 will write data supplied from the data allocator 16 to the data areaA for the transferred-word length on the basis of the physical addresssupplied from the converter 15.

In step ST70, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area B.

In step ST71, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST72. On the contrary, if thedevice 1 has decided to continuously write data, it will go back to stepST67 and repeat the operations in steps ST68 to ST71 above.

In step ST72, the composite memory device 1 judges, based on theconversion table generated in step ST62, for example, whether data hasbeen written in the data area B. In case data is found written in thedata area B, the device 1 goes to step ST73. On the contrary, in case nodata is found written in the data area B, the device 1 goes to stepST74.

In step ST73, the composite memory device 1 copies data written in thedata area B by going through steps ST61 to ST63 to the data area A. Forexample, in case data is written at memory addresses “XX0021h” to“XX0024h” in the data area B as shown in FIG. 12, the device 1 readsdata written at the “XX0021h” to “XX0024h”, and copies the read data topredetermined physical addresses “1234h” to “1237h” in the data area Awith reference to the conversion table generated in step ST62.

In step ST74, the composite memory device 1 updates the third and fourthFATs, directory and the conversion table generated in step ST62correspondingly to the new data written to the data area B by goingthrough steps ST61 to ST63 and new data written to the data area A bygoing through steps ST66 to ST68.

Next, the data write to the composite memory device 1 having ageneral-purpose host device connected to the interface 12 thereof willbe explained with reference to the flow diagram in FIG. 14.

In step ST80, the composite memory device 1 detects a blank cluster bysearching the data area A from the top of the latter after being readyfor data write to the data area A.

The processing unit 14 reads the third FAT from the data area B, anddeploys the read third FAT in the RAM. The processing unit 14 moves theselection pointer to a predetermined logical address in the third FATdeployed in the RAM, and searches logical addresses including from thepredetermined one to the end one for identification informationindicative of a blank area with the selection pointer being moved inthat direction.

In step ST81, the processing unit 14 generates a logical address of aposition for starting data write to the detected blank area, length ofdata to be transferred and a command for data writing operation, andsupplies them to the converter 15.

In step ST82, the composite memory device 1 writes data to a data areacorresponding to a predetermined physical address in the data area A.The converter 15 converts the logical address supplied from theprocessing unit 14 into a physical address on the basis of the addressconversion table, and supplies the converted physical address to the HDD10. Also, the converter 15 informs the data allocator 16 that it hasconverted the logical address supplied from the processing unit 14 intothe physical address.

In response to the information from the converter 15, the data allocator16 allocates data supplied via the interface 12 to the HDD 10. The HDD10 will write data supplied from the data allocator 16 to the data areaA for the transferred-word length on the basis of the physical addresssupplied from the converter 15.

In step ST83, the composite memory device 1 issues an interrupt to thehost device 4 after writing data for the transferred-data length to thedata area A.

In step ST84, the composite memory device 1 judges whether it shouldexit the data writing process. In case the device 1 has decided to exitthe data writing process, it goes to step ST85. On the contrary, if thedevice 1 has decided to continuously write data, it goes back to stepST80 and repeats the operations in steps ST80 to ST84 above.

In step ST85, the composite memory device 1 updates the third FAT anddirectory correspondingly to the new data written to the data area A.

Note that steps ST60 to ST74 and steps ST80 to ST85 may be programmedand these programs be executed to let the composite memory device 1 tomake the aforementioned data write.

As having been described in the foregoing, the composite memory device 1as the embodiment of the present invention is open to an externaldevice. It has the third FAT to manage the data area A and fourth FATused only in the recording medium to manage the data area B. It limitsdata write to the data area depending upon the type of a host device 4connected to the device 1 and copies data written in the data area B tothe data area A after completion of the data write, so that ageneral-purpose host device will not male any data write and read to andfrom the data area B. Therefore, even after data write is made from thegeneral-purpose device, the device 1 can write data to the recordingmedium 2 low in bit cost and nonvolatile recording medium 3 advantageousin quick response, low power consumption, etc. from a dedicated hostdevice with effective utilization of the advantages of these recordingmedia 2 and 3.

Also, in the composite memory device 1 as the embodiment of the presentinvention, since data for reproduction should be read from the data areaA, a general-purpose host device 4 can read data having been writtenfrom a dedicated host device and the dedicated host device can read datahaving been written from the general-purpose host device.

The first to third embodiments have been described in the foregoing eachas an example capable of recording a moving picture instantaneously.However, the first embodiment of the device 1 having the recordingmedium 2 low in bit cost and nonvolatile recording medium 3 advantageousin quick response, low power consumption, etc. may be adapted otherwise.Namely, when the recording medium 2 is driven up to a predeterminedvelocity or when it is in waiting state, the device 1 consumes thepower, which will adversely affect the power availability in an HDDbasedmobile device which uses a limited source of energy. Further, if any ofthe clusters on the track of the hard disk becomes defective, the datatransfer rate will be deteriorated because a normal cluster has to besubstituted for the defective one. To avoid this, the device may beadapted to always write a file which is accessed frequently or asmall-capacity file to the nonvolatile recording medium 3, whereby thepower consumption can be reduced and the power source can be made for alonger time.

Also, the composite memory device 1 according to the present inventionmay be adapted so that the FATs are managed within the recording medium2, whereby the host device 4 will advantageously be less loaded andcount out FATs increased in number correspondingly to an increasedcapacity of the data areas A and B.

Note that in case the host device 4 has the same function as those ofthe device recognition unit 13, processing unit 14 and converter 15, thecomposite memory device 1 may be adapted for the host device 4 toperform the functions of the device recognition unit 13, processing unit14 and converter 15.

Also, although the embodiments of the present invention have beendescribed above on the assumption that the recording medium 2 is a harddisk, the recording medium 2 may be a CD or DVD because arandom-accessible recording medium will be able to function as havingbeen described in the foregoing.

Also, although the FAT file system is used to manage the data areas inthe composite memory device 1, any system capable of managing data as afile may be used in place of the FAT file system.

In the foregoing, the present invention has been described in detailconcerning certain preferred embodiments thereof as examples withreference to the accompanying drawings. However, it should be understoodby those ordinarily skilled in the art that the present invention is notlimited to the embodiments but can be modified in various manners,constructed alternatively or embodied in various other forms withoutdeparting from the scope and spirit thereof as set forth and defined inthe appended claims.

1. A -composite memory device comprising: a recording medium having afirst data area assigned a first physical address; a nonvolatilerecording medium having a second data area assigned a second physicaladdress, and an identification information table assigned logicaladdresses for managing the first and second physical addresses andhaving predetermined identification information written therein at eachof the logical addresses; an interface to which a host device is to beconnected; a recognizing means for recognizing a host device connectedto the interface; an identification information table reading means forreading the identification information table from the nonvolatilerecording medium; an information selecting means for selecting a logicaladdress where the predetermined identification information is written onthe basis of the result of recognition supplied from the recognizingmeans and identification information table read by the identificationinformation table reading means; a converting means for converting alogical address selected by the identification information selectingmeans into a first predetermined physical address corresponding to thefirst data area and into a second predetermined physical addresscorresponding to the second data area; a data allocating means forallocating data supplied from the host device connected to the interfaceto the first or second data area on the basis of the conversion made bythe converting means; a first wiring means for writing the dataallocated to the first data area by the data allocating means at apredetermined location in the first data area on the basis of the firstphysical address; and a second writing means for writing the dataallocated to the second data area by the data allocating means on thebasis of the second physical address.
 2. The composite memory deviceaccording to claim 1, wherein: when informed from the recognizing meansthat the host device connected to the interface is not able to makedifferentiation between the recording medium and nonvolatile recordingmedium, the information selecting means preferentially selects one whereidentification information indicative of a blank area is written fromamong logical addresses corresponding to the first data area in anidentification information table read by the identification informationtable reading means; and when informed from the recognizing means thatthe host device connected to the interface is able to makedifferentiation between the recording medium and nonvolatile recordingmedium, the information selecting means preferentially selects one whereidentification information indicative of a blank area is written fromamong logical addresses corresponding to, the second data area in theidentification information table read by the identification informationtable reading means.
 3. A method of writing data to a composite memorydevice including a recording medium having a first data area assigned afirst physical address, a nonvolatile recording medium having a seconddata area assigned a second physical address, and an identificationinformation table assigned logical addresses for managing the first andsecond physical addresses and having predetermined identificationinformation written therein at each of the logical addresses, and aninterface to which a host device is to be connected, the methodcomprising: a recognizing step of recognizing a host device connected tothe interface; an identification information table reading step ofreading the identification information table from the nonvolatilerecording medium; an information selecting step of selecting a logicaladdress where the predetermined identification information is written onthe basis of the result of recognition supplied from the recognizingstep and identification information table read in the identificationinformation table reading step; a converting step of converting alogical address selected in the identification information selectingstep into a first predetermined physical address corresponding to thefirst data area and into a second predetermined physical addresscorresponding to the second data area; a data allocating step ofallocating data supplied from the host device connected to the interfaceto the first or second data area on the basis of the conversion made inthe converting step; a first writing step of writing the data allocatedto the first data area in the data allocating step at a predeterminedlocation in the first data area on the basis of the first physicaladdress; and a second writing step of writing the data allocated to thesecond data area in the data allocating step on the basis of the secondphysical address.
 4. A program for having a computer write data to acomposite memory device including a recording medium having a first dataarea assigned a first physical address, a nonvolatile recording mediumhaving a second data area assigned a second physical address, and anidentification information table assigned logical addresses for managingthe first and second physical addresses and having predeterminedidentification information written therein at each of the logicaladdresses, and an interface to which a host device is to be connected,the program comprising: a recognizing step of recognizing a host deviceconnected to the interface; an identification information table readingstep of reading the identification information table from thenonvolatile recording medium; an information selecting step of selectinga logical address where the predetermined identification information iswritten on the basis of the result of recognition supplied from therecognizing step and identification information table read in theidentification information table reading step; a converting step ofconverting a logical address selected in the identification informationselecting step into a first predetermined physical address correspondingto the first data area and into a second predetermined physical addresscorresponding to the second data area; a data allocating step ofallocating data supplied from the host device connected to the interfaceto the first or second data area on the basis of the conversion made inthe converting step; a first writing step of writing the data allocatedto the first data area in the data allocating step at a predeterminedlocation in the first data area on the basis of the first physicaladdress; and a second writing step of writing the data allocated to thesecond data area in the data allocating step on the basis of the secondphysical address.
 5. A composite memory device comprising: a recordingmedium having a first data area assigned a first physical address; anonvolatile recording medium having a second data area assigned a secondphysical address, and a first identification information table assignedlogical addresses for managing the first and second physical addressesand having written therein identification information that data write atthe physical addresses is refused and a second identificationinformation table assigned logical addresses corresponding to the secondphysical address and having predetermined identification is written ateach of the logical addresses; an interface to which a host device is tobe connected; a recognizing means for recognizing a host deviceconnected to the interface; an identification information table readingmeans for reading the first identification information table or thefirst and second identification information tables from the nonvolatilerecording medium on the basis of the result of recognition supplied fromthe recognizing means; an information selecting means for selecting alogical address where the predetermined identification information iswritten on the basis of the first identification information table orthe first and second identification information tables read by theidentification information table reading means; a converting means forconverting a logical address selected by the identification informationselecting means into a first predetermined physical addresscorresponding to the first data area and into a second predeterminedphysical address corresponding to the second data area; a dataallocating means for allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made by the converting means; a first wiring means forwriting the data allocated to the first data area by the data allocatingmeans at a predetermined location in the first data area on the basis ofthe first physical address; and a second writing means for writing thedata allocated to the second data area by the data allocating means onthe basis of the second physical address.
 6. The composite memory deviceaccording to claim 5, wherein: when informed from the recognizing meansthat the host device connected to the interface is not able to makedifferentiation between the recording medium and nonvolatile recordingmedium, the identification information table reading means selects thefirst identification information table from the nonvolatile recordingmedium; and when informed from the recognizing means that the hostdevice connected to the interface is able to make differentiationbetween the recording medium and nonvolatile recording medium, theidentification information table reading means selects the first andsecond identification information tables from the nonvolatile recordingmedium, and when the identification information table reading means hasread the first identification information table, the informationselecting means selects a logical address where identificationinformation indicative of a blank area is written from the firstidentification information table read by the identification informationtable reading means; when the identification information table readingmeans has read the first and second identification information tables,the information selecting means preferentially selects a logical addresswhere identification information indicative of a blank area is writtenfrom the second identification information table; and when there is noblank area in the second identification information table, theinformation selecting means selects a logical address whereidentification information indicative of a blank area is written fromthe first identification information table.
 7. The composite memorydevice according to claim 5, wherein the identification information thatit is refused to write data written in the first identificationinformation table is refused is pseudo identification informationindicating that data is already written in the second data area, pseudoidentification information indicating that the second data area is adefective cluster, pseudo identification information indicating that thesecond data area is outside the data area or pseudo identificationinformation indicating an EOF (end of file).
 8. A method of writing datato a composite memory device including a recording medium having a firstdata area assigned a first physical address, a nonvolatile recordingmedium having a second data area assigned a second physical address, anda first identification information table assigned logical addresses formanaging the first and second physical addresses and having writtentherein identification information that data write at the physicaladdresses is refused and a second identification information tableassigned logical addresses corresponding to the second physical addressand having predetermined identification is written at each of thelogical addresses, and an interface to which a host device is to beconnected, the method comprising: a recognizing step of recognizing ahost device connected to the interface; an identification informationtable reading step of reading the first identification information tableor the first and second identification information tables from thenonvolatile recording medium on the basis of the result of recognitionsupplied from the recognizing means; an information selecting step ofselecting a logical address where the predetermined identificationinformation is written on the basis of the first identificationinformation table or the first and second identification informationtables read in the identification information table reading step; aconverting step of converting a logical address selected in theidentification information selecting step into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area; adata allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means; a first wiring step ofwriting the data allocated to the first data area in the data allocatingmeans at a predetermined location in the first data area on the basis ofthe first physical address; and a second writing step of writing thedata allocated to the second data area in the data allocating step onthe basis of the second physical address.
 9. A program for having acomputer write data to a composite memory device including a recordingmedium having a first data area assigned a first physical address, anonvolatile recording medium having a second data area assigned a secondphysical address, and a first identification information table assignedlogical addresses for managing the first and second physical addressesand having written therein identification information that data write atthe physical addresses is refused and a second identificationinformation table assigned logical addresses corresponding to the secondphysical address and having predetermined identification is written ateach of the logical addresses, and an interface to which a host deviceis to be connected, the program comprising: a recognizing step ofrecognizing a host device connected to the interface; an identificationinformation table reading step of reading the first identificationinformation table or the first and second identification informationtables from the nonvolatile recording medium on the basis of the resultof recognition supplied from the recognizing means; an informationselecting step of selecting a logical address where the predeterminedidentification information is written on the basis of the firstidentification information table or the first and second identificationinformation tables read in the identification information table readingstep; a converting step of converting a logical address selected in theidentification information selecting step into a first predeterminedphysical address corresponding to the first data area and into a secondpredetermined physical address corresponding to the second data area; adata allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means; a first wiring step ofwriting the data allocated to the first data area in the data allocatingmeans at a predetermined location in the first data area on the basis ofthe first physical address; and a second writing step of writing thedata allocated to the second data area in the data allocating step onthe basis of the second physical address.
 10. A composite memory devicecomprising: a recording medium having a first data area assigned a firstphysical address; a nonvolatile recording medium having a second dataarea assigned a second physical address, a first identificationinformation table assigned a second data area assigned a second physicaladdress and having predetermined identification information written atthe first logical address and a second identification information tableassigned a second logical address corresponding to the second physicaladdress and having predetermined identification information written atthe second logical address; an interface to which a host device is to beconnected; a recognizing means for recognizing a host device connectedto the interface; an identification information table reading means forreading the first and second identification information tables from thenonvolatile recording medium on the basis of the result of recognitionsupplied from the recognizing means; a first information selecting meansfor selecting the first logical address where the predeterminedidentification information is written from the first identificationinformation table read by the identification information table readingmeans; a second information selecting means for selecting the secondlogical address where the predetermined identification information iswritten from the second identification information table read by theidentification information table reading means on the basis of theresult of recognition supplied from the recognizing means; a conversiontable generating means for generating a conversion table in which thefirst logical address selected by the first information selecting meansand second logical address selected by the second information selectingmeans are associated with each other; a converting means for convertingthe first logical address selected by the first identificationinformation selecting means into a first predetermined physical addresscorresponding to the first data area and the second logical addressselected by the second information selecting means into a secondpredetermined physical address corresponding to the second data area; adata allocating means for allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made by the converting means; a first wiring means forwriting the data allocated to the first data area by the data allocatingmeans at a predetermined location in the first data area on the basis ofthe first physical address converted by the converting means; a secondwriting means for writing the data allocated to the second data area bythe data allocating means at a predetermined location in the second dataarea on the basis of the second physical address converted by theconverting means; and a third writing means for writing data written inthe second data area by the second writing means at a predeterminedlocation in the first data area on the basis of the conversion tablegenerated by the conversion table generating means.
 11. The compositememory device according to claim 10, wherein: when informed from therecognizing means that the host device connected to the interface is notable to make differentiation between the recording medium andnonvolatile recording medium, the identification information tablereading means selects the first identification information table fromthe nonvolatile recording medium; and when informed from the recognizingmeans that the host device connected to the interface is able to makedifferentiation between the recording medium and nonvolatile recordingmedium, the identification information table reading means selects thefirst and second identification information tables from the nonvolatilerecording medium.
 12. A method of writing data to a composite memorydevice including a recording medium having a first data area assigned afirst physical address, a nonvolatile recording medium having a seconddata area assigned a second physical address, a first identificationinformation table having a second data area assigned a second physicaladdress and having predetermined identification information written atthe first logical address and a second identification information tableassigned a second logical address corresponding to the second physicaladdress and having predetermined identification information written atthe second logical address, and an interface to which a host device isto be connected, the method comprising: a recognizing step ofrecognizing a host device connected to the interface; an identificationinformation table reading step of reading the first and secondidentification information tables from the nonvolatile recording mediumon the basis of the result of recognition supplied from the recognizingstep; a first information selecting step of selecting the first logicaladdress where the predetermined identification information is writtenfrom the first identification information table read in theidentification information table reading step; a second informationselecting step of selecting the second logical address where thepredetermined identification information is written from the secondidentification information table read in the identification informationtable reading step on the basis of the result of recognition suppliedfrom the recognizing step; a conversion table generating step ofgenerating a conversion table in which the first logical addressselected in the first information selecting step and second logicaladdress selected by the second information selecting means areassociated with each other; a converting step of converting the firstlogical address selected in the first identification informationselecting step into a first predetermined physical address correspondingto the first data area and the second logical address selected in thesecond information selecting step into a second predetermined physicaladdress corresponding to the second data area; a data allocating step ofallocating data supplied from the host device connected to the interfaceto the first or second data area on the basis of the conversion made inthe converting means; a first wiring step of writing the data allocatedto the first data area in the data allocating step at a predeterminedlocation in the first data area on the basis of the first physicaladdress converted in the converting step; a second writing step ofwriting the data allocated to the second data area in the dataallocating step at a predetermined location in the second data area onthe basis of the second physical address converted in the convertingstep; and a third writing step of writing data written in the seconddata area in the second writing step at a predetermined location in thefirst data area on the basis of the conversion table generated in theconversion table generating step.
 13. A program for having a computerwrite to a composite memory device including a recording medium having afirst data area assigned a first physical address, a nonvolatilerecording medium having a second data area assigned a second physicaladdress, a first identification information table having a second dataarea assigned a second physical address and having predeterminedidentification information written at the first logical address and asecond identification information table having a second logical addresscorresponding to the second physical address and having predeterminedidentification information written at the second logical address, and aninterface to which a host device is to be connected, the methodcomprising: a recognizing step of recognizing a host device connected tothe interface; an identification information table reading step ofreading the first and second identification information tables from thenonvolatile recording medium on the basis of the result of recognitionsupplied from the recognizing step; a first information selecting stepof selecting the first logical address where the predeterminedidentification information is written from the first identificationinformation table read in the identification information table readingstep; a second information selecting step of selecting the secondlogical address where the predetermined identification information iswritten from the second identification information table read in theidentification information table reading step on the basis of the resultof recognition supplied from the recognizing step; a conversion tablegenerating step of generating a conversion table in which the firstlogical address selected in the first information selecting step andsecond logical address selected by the second information selectingmeans are associated with each other; a converting step of convertingthe first logical address selected in the first identificationinformation selecting step into a first predetermined physical addresscorresponding to the first data area and the second logical addressselected in the second information selecting step into a secondpredetermined physical address corresponding to the second data area; adata allocating step of allocating data supplied from the host deviceconnected to the interface to the first or second data area on the basisof the conversion made in the converting means; a first wiring step ofwriting the data allocated to the first data area in the data allocatingstep at a predetermined location in the first data area on the basis ofthe first physical address converted in the converting step; a secondwriting step of writing the data allocated to the second data area inthe data allocating step at a predetermined location in the second dataarea on the basis of the second physical address converted in theconverting step; and a third writing step of writing data written in thesecond data area in the second writing step at a predetermined locationin the first data area on the basis of the conversion table generated inthe conversion table generating step.